A cat can easily become pregnant if she has intercourse with an unneutered male cat (tom cat), while she is sexually excited. The gestation period in cats normally lasts for a period of 60-67 days. Pregnant cats (also known as 'Queens') show various psychological and physical changes during this period, which become more evident three weeks after breeding. If you are unable to ascertain if your cat is pregnant, take her to a veterinarian. The doctor can feel the abdomen and easily detect any signs of pregnancy. Radiotherapy or X-rays can also help in diagnosing feline pregnancy.

Physical Changes
There are few noticeable changes during the first couple of weeks. For 4-5 weeks, it is very difficult to determine if a cat is pregnant. The animal gains a few extra pounds and the abdomen enlarges only after the fifth week. Enlargement of the abdomen depends on the size of the litter inside the womb. The nipples become pinkish and the surrounding hairs slightly recede. Visible enlargement of the mammary gland occurs after the seventh week. The mother generally starts producing milk two days after delivery.

Behavioral Changes
Many conspicuous behavioral changes are noticeable in your pet during the gestation period. In the last few weeks of the pregnancy, a cat might display various symptoms like restlessness and anxiety. The animal might also avoid socialization and seek solitude. The growing discomfort of an enlarged abdomen during the last three weeks, might also make her a bit violent, if teased or disturbed. She might also frequently soil the house during the last few weeks, as the growing uterus presses on the bladder or colon.

Tips for Owner
When you are sure that your feline has had a successful mating, it is your duty to keep a check on her overall health. Feed a well-balanced diet and lots of fluids to the expecting mother, so that she gives birth to strong and healthy kittens. A pregnant cat tends to get hungry easily. So provide her with large servings. Chart out a diet plan after consulting a veterinarian. Do not include any supplements unless advised by the vet, to avoid unnecessary overdose. Also provide her with a good 'birthing box' or 'nest bed' lined with old newspapers and sheets. Place it in a secluded and warm corner of the house, away from harsh lighting and noise.